The former equalities minister Harriet Harman was forced to apologise last night for branding the Chief Secretary to the Treasury, Danny Alexander, a "ginger rodent".

Ms Harman, Labour's deputy leader, admitted she had been "wrong" to use the description during a speech at the Scottish Labour conference in Oban. She also called the Liberal Democrat "the front-man for the Tory cuts".

Her remarks were attacked for being anti-Scottish, given that 13 per cent of Scots have red hair compared with just 2 per cent of the population globally. For his part, Mr Alexander insisted he was not ashamed of his colouring. "I am proud to be ginger and rodents do valuable work cleaning up mess others leave behind," he said via Twitter.

A spokeswoman for the Labour Party said yesterday: "Harriet Harman has apologised for her comment about Danny Alexander and says it was wrong."